Abstract
This chapter argues that a Peircean philosophy of sex offers a non-reductionist approach to sex as a biological category. The chapter surveys traditional biological accounts of sex categories and several social constructivist accounts of sex. It then provides an overview of Peirce’s scholastic realism and his ethics of inquiry. While Peirce regarded the distinction between the sexes as a rare “polar distinction”, the chapter works to recover the nuanced view of sex that Peirce ought to have adopted had he extended his scholastic realism to reproductive biology. Ultimately, the Peircean account offered treats sex differences as norms expressed as bimodal distributions. The chapter concludes by illustrating some applications of this Peircean philosophy of sex, and gesturing to those that we can yet barely imagine.